Middle distillate masking agent



United States Patent 3,151,956 MIDDLE DISTILLATE MASKING AGENT Edwin C. Younghouse, Cranford, N.J., assignor to Esso Research and Engineering Company, a corporation of Delaware N0 Drawing. Filed Feb. 16, 1961, Ser. No. 89,644 3 Claims. (Cl. 44-59) The present invention is concerned with improved fuels with respect to exhaust odor characteristics boiling in the range from about 250 to 750 F. More particularly, the invention relates to improved diesel fuel compositions wherein the diesel fuel contains an odor masking agent so as to mitigate the obnoxiousness of exhaust fumes from diesel engines. The composition, in accordance with the present invention, comprises a middle distillate fuel in combination with a masking composition comprising benzyl salicylate. The benzyl salicylate is particularly effective in combination with vanillin, artificial musks (tertiary butyl nitro benzenes), diethyl phthalate, ionone, eugenol, and oxo heavy fractions.

It is well known in the art to burn middle distillate fuels under various conditions. It is known, for example, to burn diesel fuels in diesel engines wherein the odors evolved are ill-smelling and obnoxious. In accordance with the present invention, a composition is utilized comprising a middle distillate having in combination therewith a masking formulation comprising benzyl salicylate. It is preferred that the masking composition comprise benzyl salicylate in combination with oxo bottoms.

It is therefore the principal object of the present invention to set forth an improved masking agent for middle distillates, particularly for diesel fuels. The boiling ranges of these fuels are generally from about 250 to 750 F.

The petroleum distillate fuels in which the additive materials of the invention are employed consist of a major proportion, at least 95%, of liquid hydrocarbons boiling at temperatures between about 100 F. and about 750 F. These fuels include aviation turbine engine fuels such as JP-l, JP-4 and JP-S fuels, and diesel fuels such as marine, stationary and automotive diesel engine fuels.

Aviation turbine engine fuels consist of at least 95% of a mixture of volatile hydrocarbons. It is defined by US. Military Specifications Mll.-F5616 and MIL-F- 5624C. Its volatility is such that its end point does not exceed 572 F. Its viscosity is between 0.5 and 1.5 centistokes at 100 F.

Diesel fuels as referred to in connection with the invention consist of at least 95% of a mixture of hydrocarbons boiling between 250 F. and 750 F. either by ASTM Method D8656 when their end points do not exceed 600 F. or by ASTM Method D158-54. Diesel fuels are defined by ASTM Specification D-975-5 3T and fall into Grades 1D, 2D and 4D, in all of which the additive materials of the invention may be used. They have viscosities between 1.4 and 26.4 centistokes at 100 F.

The liquid fuels in which the additive materials may be incorporated thus comprise at least 95% by weight of a mixture of hydrocarbons having a boiling range between the limits of 100 F. and 750 F. and a viscosity between the limits of 0.5 and 26.4 centistokes at 100 F.

One ingredient of the masking composition of the present invention comprises benzyl salicylate in combination "k with vanillin r CHO OCH and also in combination with an effective amount of oxo bottoms.

3,151,956 Patented Oct. 6, 1964 As pointed out heretofore, the benzyl salicylate is particularly effective when used in combination with oxo bottoms. The oxo bottoms product is produced by what is now the well known two-stage process for producing oxo alcohols (see e.g. US. Patent 2,327,066). In the first stage an olefinic material, a carbonylation catalyst, and CO and H are reacted to give a product which consists predominantly of aldehydes. This material is catalytically hydrogenated in the second stage to give the corresponding alcohols. The overall reaction may be formulated as follows:

Both the aldehyde and the alcohol formed as a result of the reaction contain one more carbon atom than the olefinic material from which they are derived.

The carbonylation, or oxo stage, as it is sometimes called, is Widely useful and is used effectively with both long and short chain olefinic compounds, depending on the type alcohol desired. Thus, straight and branch chained olefins and diolefins such as propylene, butylene, butadiene, pentene, pentadiene, hexene, heptene, olefin polymers such as diand tri-isobutylene, the hexene and heptene dimers, polypropylenes, and olefinic fractions from the hydrocarbon synthesis process or from thermal or catalytic cracking operations, and other sources of hydrocarbon fractions containing such olefins may be used as starting materials, depending on the nature of the final product desired. In general, olefins having up to about 18-20 carbon atoms in the molecule are preferred in this reaction. Olefins of C to C ranges are, of course, required to prepare the commercially preferred C to C alcohols.

The catalysts for the first stage of the process are usually employed in the form of the catalytically active metal salts of high molecular weight fatty acids such as stearic, palmitic or oleic, naphthenic acids and similar acids. Thus, examples of suitable catalysts are such organic salts as cobalt stearate, oleate, or naphthenate or iron linoleate. These salts are soluble in the liquid olefin feed and may be supplied to the first reaction zone as hydrocarbon solutions, preferably dissolved in the olefin feed.

The synthesis gas mixture fed to the first stage may consist of any ratio of H to CO, but preferably these two gases are present at about one volume hydrogen per volume of CO. The conditions for the reaction of olefins with H and CO vary somewhat in accordance with the nature of the olefin feed, but the reaction is generally conducted at pressures in the range of about 1500 to 4500 p.s.i.g., and at temperatures in the range of about to 450 F.

The hydrogenation stage may be operated at conventional hydrogenation conditions which include temperatures, pressures, gas and liquid feed rates approximately within the ranges specified above for the first stage. Variout known types of hydrogenation catalysts such as nickel, tungsten, molybdenum, their oxides and sulfides and oth ers may be used. These include catalysts of both the sulfur sensitive and sulfur insensitive types. The catalyst may be supported on some suitable carrier such as charcoal. The liquid product from the hydrogenation stage is worked up by distillation to separate the desired alcohols from unconverted olefinic feed material, unhydrogenated carbonyl compounds, and saturated hydrocarbons formed in the process.

In the hydrogenation stage, in the presence of the hydrogenation catalysts and under the conditions employed, further condensations and reactions of the initially formed 3 aldehydes and alcohols take place to give additional high boiling impurities which are generally allowed to remain as the bottoms after the distillation of the main portion of the alcohol is completed.

In a process for the manufacture of iso-octyl alcohol by a two-stage Oxo process using a predominantly C olefinic feed, the final distillation of the crude C alcohol product results in a bottoms fraction representing about 15-30% of the crude alcohol charge to the distillation zone. This bottoms fraction consists of C and some C alcohols, as well as C C alcohols, C acetals and C ethers. Of these constituents, the C alcohols represent the final traces (15%) remaining in the bottoms from the distillation of the main product. The remaining socalled bottoms consists primarily of higher boiling oxygenated compounds formed by side reactions as outlined above occurring in either the first or second stage of the C alcohol process. As clearly as can be determined by chemical analysis and infra-red absorption spectrographic study, these constituents were identified as C secondary alcohols, C aldehydes or ketones, C acetals, C 'festers of C naphthenic acids used in making the cobalt catalyst for the first or oxonation stage, and saturated and unsaturated C ethers. A typical chemical analysis of the higher boiling oxygenated compounds obtained in a plant, and free from C -C alcohols fraction, is shown in Table I. The hydroxyl number, free and combined carbonyl numbers and saponification and acid numbers are expressed in terms of milligrams of potassium hydroxide per gram of sample analyzed.

TABLE I Typical Composition of the Oxo Alcohol Bottoms 1 Calculated by ditference.

Analytical results obtained by chemical and'infra-red methods are in good agreement as indicated by their comparison in Table II below:

TABLE II Comparison of Analyses of x0 Alcohol Bottoms Chemical Infra-red Method Method Percent C r-Cm Alcohols" 48. 6 43 Percent 015-015 Ketones- 0. 2 4 Percent C Ester 14. 7 13 Percent 024 Acetal" 19.1 9 Percent Acid Trace Percent Saturated Cm Ether 17.4 27 Percent Unsaturated Cm Ether 3 Thus, it can readily be seen that the synthetic oxo processes give complex mixtures of compounds having various carbon structures in the molecules and having varied molecular weights. (As to the complex nature of these products see United States Bureau of Mines Publication, RT. 4270, Critical Review of Chemistry of Oxo Synthesis, Etc, June 1948.)

The bottoms product from the C olefin feed substantially free of C alcohols, boils in the range of about 190 C. to about 18 weight percent, boiling above 395 C. It is to be understood that Whenever the term Oxo Bottoms is used in the specification, it indicates a still bottoms product produced by the indicated two-stage operation.

When benzyl salicylate is used alone, it is preferred that the concentration be in'the range from about 0.001 to 0.2 wt. percent, preferably in the range from about 0.01 to 0.1 wt. percent based upon the amount of base diesel fuel. When the benzyl salicylate is used in conjunction with other masking agents, such as 0X0 bottoms, it is preferred that the amount of benzyl salicylate be in the range from about 0.002 to 0.1 wt. percent, preferably in the range from 0.005 to 0.1 wt. percent and that the amount of oxo bottoms present be present in the concentration in the range from about 0.005 to 2.0 wt. percent, preferably in the range from 0.01 to 1.0 wt. percent.

The present invention may be more fully understood by the following examples illustrating the same. Data were determined on a diesel fuel burned in a General Motors diesel engine 4171B wherein the rpm. idle was 650, the jacket Water temperature was 160 F., and the fuel temperature was F. Tests were determined by the following procedure.

The four cylinder GM 4171B diesel engine was so equipped that one fuel could be burned in one set of cylinders (Nos. 1 and 2) and at the same time a different fuel burned in the other set of cylinders (3 and 4). Also, the exhausts for these sets of cylinders were divided, so they could be sampled independently. In this manner the exhaust fumes from the base diesel fuel could be compared in odor with the fumes from the treated fuel (base fuel plus additive).

In order to reduce the chances of correct guesses, an odor triangulation test method was used. Each odor panelist sniffed three samples of exhaust fumes, but two were from the same source (set of cylinders). The panelist was asked first to select the exhaust sample which had a different odor (a No difference choice was also possible). If he found one odor to be different he was asked if he preferred it to the other two. The preference ratio refers to the number of panelists who preferred the treated fuel to the total number of panelists who took the test (whether or not they found the correct odor difference).

In most evaluations of the odor masking additives, the treated fuel was first compared with the base fuel in one set of cylinders (Nos. 1 and 2). Later the treated fuel was switched over to cylinders 3 and 4 and again compared with the base fuel (now in cylinders 1 and 2). This procedure minimized the cylinder to cylinder differences in exhaust odor.

RESULTS OF ODOR TRIANGULATION TESTS IN GMD 4171 ENGINE-KEROSENE FUEL 0.005% benzyl salicylate or 0.015% oxo bottoms are ineifective alone. However, the mixture of the two is very effective in improving odor.

What is claimed is:

1. Diesel fuel composition of improved exhaust odor qualities which consists essentially of a hydrocarbon distillate boiling in the range from 250 F. to 750 F., from about 0.002 wt. percent to 0.5 wt. percent of benzyl salicylate, and from about 0.002 wt. percent to 0.5 wt.

percent of 0x0 bottoms based upon the weight of the base fuel.

2. Composition as defined by claim 1 wherein the amount of oxo bottoms present is about 0.015 wt. percent and the amount of benzyl salicylate present is about 0.005 wt. percent.

3. Composition as defined by claim 2 wherein about 0.0025 wt. percent of musk xylene is present based upon the base fuel.

References Cited in the file of this patent UNITED STATES PATENTS 58,905 Spangle Oct. 16, 1866 1,980,097 Ruddies Nov. 6, 1934 2,955,928 Smith et a1. Oct. 11, 1960 6 FOREIGN PATENTS France May 15, 1924 France Aug. 12, 1929 Germany May 4, 1934 Germany May 5, 1934 Great Britain Apr. 6, 1895 Great Britain Nov. 7, 1917 Great Britain Oct. 29, 1931 Great Britain Jan. 11, 1934 OTHER REFERENCES Uses and Applications of Chemicals and Related Materials, Gregory, Reinhold Publ. Corp., recd June 2, 1944,

page 240.

15 The Merck Index, sixth edition, Merck & Company,

1952, page 137. 

1. DIESEL FUEL COMPOSITION OF IMPROVED EXHAUSE ODOR QUALITIES WHICH CONSISTS ESSENTIALLY OF A HYDROCARBON DISTILLATE BOILING IN THE RANGE FROM 250*F. TO 750*F., FROM ABOUT 0.002 WT. PERCENT TO 0.5WT. PERCENT OF BENZYL SALICYLATE, AND FROM ABOUT 0.002 WT. PERCENT TO 0.5 WT. PERCENT OF OXO BOTTOMS BASED UPON THE WEIGHT OF THE BASE FUEL. 